Method and a system for managing a personal event log specific to an operating activity executed on a hardware perimeter of computer resources, and memory implemented in the system

ABSTRACT

This method of managing a personal event log specific to an operating activity executed on a multiple-cell computer platform comprises:  
     while an activity is saving an event, a step of recording the event in a common event log together with an identifier of the activity that is saving the event; and  
     prior to an activity consulting its personal event log, a step of reconstructing the personal event log from the common event log, said reconstruction step including an operation of selecting from the common event log only those events which are associated with the identifier of the activity in order to include those events in the personal event log reconstructed for said activity.

[0001] The invention relates to a method of managing a personal log ofevents containing events recorded by an operating activity beingexecuted on a perimeter of computer resources configured on amultiple-cell computer platform.

[0002] More precisely, the method relates to multiple-cell computerplatforms having a plurality of distinct computer resource perimetersthat can be activated on the platform in succession or simultaneously.

BACKGROUND OF THE INVENTION

[0003] At present, one of the directions in which hardware and/orcomputer systems are progressing lies in maximizing the flexibility ofconfigurable computer resources to the benefit of a user havingconsiderably smaller computer resources available locally.

[0004] In present configurable or reconfigurable computer systems, asshown in FIG. 1, use is made of a multiple-cell platform PF of computerresources. The multiple-cell platform PF comprises a plurality ofcalculation cells C_(kj) each comprising at least one central processorunit and local working memories, including a non-volatile random accessmemory (NVRAM). The working memories in each of the cells are suitablein particular for containing an event log in which there are recordedevents that have taken place during the operation of the cell or of agroup of cells. By way of example, these events can be hardwareincidents or alarms that occur during operation of the cell, or they canbe events that are recorded by an operating system as it executes onsaid cell. Such an event log is also referred to as a system event log(SEL).

[0005] In configurable or reconfigurable systems of the kind shown inFIG. 1, there are resources which are common to all of the cells of theplatform. These common resources include mass memories, and inparticular system hard disks and data hard disks. Data disks containapplications software (commonly referred to as “applications”)comprising computer programs to be executed and/or data to be processed.Each disk system has an operating system suitable for managing thehardware resources of a cell or of a group of cells. In particular, eachoperating system is suitable for managing the event log of the cell orthe group of cells on which it is executed. By way of example, in FIG.1, the common resources comprise a data disk DD₁ containing anapplication L₁, a system disk DS₁ containing an operating system OS₁, adata disk DD₂ containing an application L₂, and a system disk DS₂containing an operating system OS₂.

[0006] In the context of configurable or reconfigurable systems, theterm “operating activity” applies to all of the software means needed toimplement a function that a user of the system seeks to achieve.Examples of such functions include, for example: drawing up pay sheetsand generating lists of customers to be contacted. An activity thusincludes at least one operating system suitable for managing thehardware resources of the platform. The function desired by the user isgenerally not performed by the operating system alone, and an operatingactivity commonly includes, in addition, one or more applications forexecution on the operating system to perform the function(s) desired bythe user. In this case, an activity A₁ comprises the application L₁ andthe operating system OS₁.

[0007] To maximize flexibility in such systems, common resources areconnected to the platform PF via addressable interconnection means MIimplementing a storage area network (SAN) architecture. Theinterconnection means MI are designed to give access to the commonresources from any one of the cells or from any group of cellsconfigured on the platform PF. Thus, a data disk may be accessed from acell C_(kj) in a given configuration of the platform PF, andsubsequently by a cell C_(kj+1) in the context of a differentconfiguration of the platform. Such interconnection means MI aretherefore suitable for enabling all of the cells of the platform toaccess the common resources without that requiring any kind of rewiringoperation.

[0008] Finally, configurable or reconfigurable computer systems alsocomprise a management tool MT enabling a user to group computer hardwareresources together as “perimeters” of computer resources P_(i) forexecuting operating activities A_(i). Each perimeter P_(i) is made up ofa group of cells C_(kj) and a fraction of the common resources such as adata disk and at least one system disk. In such systems it is possibleto define a plurality of perimeters P_(i). For example, in FIG. 1, twoperimeters P₁ and P₂ have been configured, both of which are configuredto execute activity A₁. The perimeter P₁ as outlined in dotted linescomprises a first group of cells, the data disk DD₁ and the system diskDS₁. The perimeter P₂, as outlined in dot-dashed lines, comprises asecond group of cells different from the first group of cells, the datadisks DD₁, and the system disk DS₁.

[0009] When two perimeters such as the perimeters P₁ and P₂ in FIG. 1share common hardware resources, such as the same system disk, in thiscase DS₁, they must be configured in succession on the same platform.Otherwise, they can be configured simultaneously on the platform PF.

[0010] Such systems correspond to systems or machines that are commonlyreferred to as “partition machines”. Normally they make it possible toinstall and execute different operating activities A_(i) simultaneouslyor successively in different perimeters of the platform. Nevertheless,such systems are not capable at present of allowing a user to restartthe same activity in a perimeter other than the perimeter in which itwas executed initially. Thus, for example, if the user seeks to restartactivity A₁, not in perimeter P₁, but in perimeter P₂, then the datarecorded in the event log by the activity A₁ while being executed on theperimeter P₁ is lost. The event log of perimeter P₁ is recorded inworking memories that are local to the perimeter P₁ and it is notaccessible from perimeter P₂. This loss of information on transfer of anactivity from an original perimeter to a destination perimeter can leadto the activity functioning wrongly when it is executed on the newperimeter.

OBJECTS AND SUMMARY OF THE INVENTION

[0011] The invention seeks to remedy that drawback by proposing a methodof managing a perimeter event log that is capable of allowing the sameoperating activity to be restarted on a perimeter other than theperimeter on which it was executed initially.

[0012] The invention thus provides a method as defined above formanaging a personal event log containing events recorded by an operatingactivity, the method comprising:

[0013] while an activity is saving an event, a step of recording theevent in a common event log together with an identifier of the activitythat is saving the event; and

[0014] prior to an activity consulting its personal event log, a step ofreconstructing the personal event log from the common event log, saidreconstruction step including an operation of selecting from the commonevent log only those events which are associated with the identifier ofthe activity in order to include those events in the personal event logreconstructed for said activity.

[0015] In the above-described method, regardless of the perimeter onwhich an activity is restarted, the events recorded by said activity inthe log during earlier execution on another perimeter are not lost. Theevents recorded by the activity are recorded in association with anidentifier of said activity in a common event log which is accessiblefrom all of the configured or configurable perimeters on the platform.Thus, even if the activity is restarted subsequently on anotherperimeter different from the perimeter on which it was being executedbeforehand, it still has access to the common event log. In addition,since the events it recorded in the common event log are associated withits own identifier, it is possible to select and return to said activityonly those events which concern it, i.e. only those events which it hasitself recorded. As a result, with respect to an event registered by orfor an activity in the common event journal, it does not matter whethersaid activity is executed on one particular perimeter or on another.

[0016] According to other characteristics of a method of managing anevent log in accordance with the invention:

[0017] the computer hardware resources of perimeters are capable ofgenerating events, and the method further comprises a step of recordingin the common event log an event that has been generated by a computerhardware resource together with an identifier of the resource that hascaused the event, and the step of reconstructing a personal event logspecific to an activity further includes an operation of selecting fromthe common event log only those events which are associated with theidentifier of a computer hardware resource contained in the perimeter onwhich said activity is being executed in order to include those eventsin the personal event log reconstructed for said activity;

[0018] while an activity is saving an event, the method furthercomprises a step of recording in the common event log a scope attributeassociated with said event and specifying the activities which areauthorized to consult said event and/or the perimeters from whichactivities are authorized to consult said event, and the step ofreconstructing a personal event log specific to an activity furtherincludes an operation of selecting from the common event log only thoseevents which are associated with a scope attribute authorizing saidevent to be consulted by the activity being executed and/or from theperimeter on which sai d activity is being executed in order to includethose events in the personal event log reconstructed for said activity;and

[0019] the method further comprises:

[0020] while an activity is sending an instruction to modify at leastone event in its personal event log, a step of recording in a file saidinstruction in association with an identifier of the activity, whichfile is accessible by the activity from all of the perimeters of theplatform; and

[0021] prior to an activity consulting its personal event log, a step ofexecuting the modification instruction applied to the personal event logas reconstructed for said activity during the reconstruction step.

[0022] The invention also provides a system for managing a personalevent log specific to an operating activity while it is being executed,the system comprising:

[0023] a multiple-cell computer platform;

[0024] a management tool suitable for defining computer hardwareresource perimeters and for activating said perimeters on the platformsimultaneously or in succession, each perimeter comprising one or morecalculation cells; and

[0025] means for storing operating activities, each operating activitycomprising at least one operating system suitable for managing thecomputer resources of the perimeter on which the activity is to beexecuted;

[0026] the system further comprising:

[0027] a memory containing a common event log suitable for storing theevents recorded by all of the operating activities;

[0028] a module for recording events in the common event log, saidevents being generated by each operating activity and being associatedwith an identifier of the activity causing the event to be saved; and

[0029] a reconstruction module for reconstructing a personal event logspecific to an operating activity from a common event log, thereconstruction module including a selection submodule for selecting fromthe common event log only those events which are associated with theidentifier of said operating activity in order to include those eventsin the personal event log reconstructed for said activity.

[0030] According to other characteristics of a system for managing anevent log in accordance with the invention:

[0031] the personal event log specific to an operating activity containsevents recorded by the computer hardware resources of the perimeter onwhich the activity is being executed, and the system further comprises amodule for recording in the common event log an event generated by acomputer hardware resource of the perimeter in association with anidentifier of said resource, and the module for reconstructing apersonal event log specific to an activity further comprises a submodulefor selecting from the common event log only those events which areassociated with an identifier of a computer hardware resource containedin the perimeter on which said activity is being executed, in order toinclude those events in the personal event log reconstructed for saidactivity;

[0032] the system further comprises a module for saving in the commonevent log a scope attribute associated with each event and specifyingthe activities which are authorized to consult said event and/or theperimeters from which the activities are authorized to consult saidevent, and the module for reconstructing a personal event log specificto an activity further comprises a submodule for selecting from thecommon event log only those events which are associated with a scopeattribute that authorizes said event to be consulted by the activitybeing executed and/or from the perimeter on which the activity is beingexecuted in order to include those events in the personal event logreconstructed for said activity; and

[0033] the system also comprises:

[0034] a recording module for recording instructions to modify at leastone event in the personal event log specific to an activity, saidrecording module being suitable for recording in the memory saidmodification instructions in association with an identifier of theactivity that has generated the instruction; and

[0035] a module for executing modification instructions recorded by anactivity in the memory, said modification instructions being applied tothe personal event log reconstructed for said activity by thereconstruction module.

[0036] The invention also provides a memory for storing information foruse in a system of the invention for managing a personal event log, thememory containing a common event log containing a list of events savedby a plurality of different operating activities, each of said eventsbeing associated with an identifier for the activity which saved it.

[0037] According to other characteristics of an information storagememory in accordance with the invention:

[0038] the common event log also contains a list of events saved bycomputer hardware resources contained in perimeters, each of said eventsbeing associated with an identifier of the computer hardware resourcethat saved it; and

[0039] the common event log contains a scope attribute associated witheach saved event, said scope attribute indicating the activities whichare authorized to consult said event and/or the perimeters from whichactivities are authorized to consult the event.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention will better understood on reading the followingdescription given purely by way of example and made with reference tothe drawings, in which:

[0041]FIG. 1 is a diagram of a known multiple-cell platform;

[0042]FIG. 2 is a diagram showing the hardware architecture of a systemin accordance with the invention;

[0043]FIG. 3 shows an example of a common event log implemented in thesystem of FIG. 2; and

[0044]FIG. 4 is a flow chart for a method of managing a personal eventlog in accordance with the invention.

MORE DETAILED DESCRIPTION

[0045]FIG. 2 shows a configurable system 2 of computer resourcescomprising a multiple-cell platform 4 connected via interconnectionmeans 6 to common computer resources 8. The platform 4 is also connectedto a management tool 9 of the platform 4.

[0046] In this case, by way of example, the common computer resourcesare constituted solely by mass memories. In this case, the mass memoriescomprise two data hard disks 10 and 12 and two system hard disks 14 and16. The data disks 10 and 12 serve to contain applications together withthe data that is to be processed. In this case, the data disk 10contains an application 20 and the data disk 12 contains an application22. These data disks 10 and 12 also contain data for processing. By wayof example, the applications 20 and 22 are software for managingdatabases or software for managing hardware resources.

[0047] In this case, the system disks 14 and 16 contain respectiveoperating systems 24 and 26. These operating systems 24 and 26 aresuitable for running the hardware computer resources of the platform 4.Thus, each operating system provides the function of managing an eventlog by means of a set of instructions for controlling the event log.This function is run at the initiative of software running on theoperating system, or else it is run at the initiative of the operatingsystem itself. In this case, the set of instructions used is a standardset of instructions complying with the specification of the standardintelligent platform management initiative (IPMI) interface as definedby Intel. This specification defines both the hardware interface withwhich the platform 4 must be equipped, i.e., for example, informationstorage registers, and also the software interface, i.e., for example,the peripheral drivers with which the operating system must be provided.This set of instructions includes in particular an instruction enablingthe event log to be consulted, an instruction for saving a new event inthe event log, and an instruction for deleting the event log.

[0048] By way of example, a first operating activity A₁ is implementedwhen the application 20 is executed on the operating system 24. Thisactivity A₁ thus comprises the application 20 and the operating system24 taken together.

[0049] The multiple-cell platform 4 is subdivided into a plurality ofcalculation cells. In this case, the platform 4 has four calculationcells 30, 32, 34, and 36 that are identical. As a result only the cell30 is described in detail.

[0050] The cell 30 is suitable, on its own or in cooperation with othercells, for executing the operating activities recorded in the commonresources. For this purpose, this cell or group of cells is run by theoperating system of the activity, as recorded in the common resources.

[0051] The cell 30 also comprises a central processor unit 40 connectedvia a data and address bus to an input/output card 42 and to localworking memories 44. The data and address bus is also connected to a set46 of cards providing an interface with the management tool 9 of theplatform 4.

[0052] The central processor unit 40 serves to execute calculationoperations. For this purpose, in the embodiment described herein, itcomprises eight 64-bit microprocessors suitable for performing thesecalculation operations in parallel and simultaneously.

[0053] The input/output card 42 serves to exchange information betweenthe common resources 8 and the cell 30.

[0054] The local working memories 44 include a unique cell identifier.For example, in this case the identifier is an order number enablingthis cell 30 to be distinguished from the other cells of the platform 4.The identifiers of the respective cells 30, 32, 34, and 36 are notedherein as C₁, C₂, C₃, and C₄.

[0055] The set 46 of interface cards comprises, in this case, twointerface cards 48 and 50. The card 48 is connected to the cells 30 and36, while the card 50 is connected to the cells 32 and 34. These cards48 and 50 are connected to the management tool 9. They are identical toeach other and only the card 48 is described herein.

[0056] The card 48 is suitable for managing the hardware resources ofthe cells 30 and 36. For example, this card is suitable for directlydetecting operating errors in the hardware components making up thecells 30 and 36 independently of the operating system executed on them.In this case, the card is adapted to send messages to the managementtool 9, each message containing an event for recording in an event log.These events relate to the hardware resources of the cell 30 or 36. Theyare sent in association with the cell identifier. By way of example, anevent might be an operating error or a technical incident that hasoccurred on a component of the cell 30 or 36.

[0057] These cards are also suitable for intercepting accesses made bythe operating system to the hardware resources of the cells. For eachcell, these cards have an IPMI hardware interface complying with theIPMI initiative specifications, in such a manner that the instructionsfor managing the event log of each cell as generated by the operatingsystem it is running are sent to this IPMI hardware interface. In thiscase, the cards 48 and 50 are suitable for relaying immediately to themanagement tool 9 all event log management instructions intercepted bymeans of the IPMI interface. These instructions are sent to themanagement tool 9 in association with a unique identifier enabling theactivity that issued the instruction to be identified.

[0058] The interconnection means 6 are suitable for connecting any oneof the cells of the platform 4 to any one of the disks 10, 12, 14, and16. Thus, because of the presence of the interconnection means 6, norewiring operation is required in order to connect any one of the disksto any of the cells of the platform 4. These interconnection means areconstituted, for example, by a dedicated data storage network complyingwith SAN architecture and built up using fiber channel switches as sold,for example, by the supplier Brocade Communications Systems, Inc., 1745Technology Drive, San Jose, Calif. 95110, USA under the references SW3800 or SW 2040. The management tool 9 is suitable for managing theconfiguration of the platform 4. For example, it is implemented using acomputer 62 which is distinct from the platform 4, having a screen and akeyboard, and associated with memory 64.

[0059] The memory 64 contains a list of domains 70 and a common eventlog 72.

[0060] The list 70 contains the definition of a plurality of logicaldomains that might be activated on the platform 4. A logical domaincombines both an identity file and a file defining a hardware perimeterof computer resources. The identity file contains a unique identifierfor an operating activity to be executed together with attributes forsaving the execution context of said activity. In particular, thesesaved attributes are intended to contain all of the configurationparameters needed for execution of the operating system of the activityso that the operating system can be executed with the same configurationparameters on any perimeter. This is how the operating system is madeindependent of the hardware resource perimeter on which it is or will beexecuted. These saved attributes include one for storing managementparameters relating to a personal event log specific to the activity.This saved attribute is suitable, for example, for storing the instantat which the activity issued its most recent instruction to delete itspersonal event log. The identity file also contains information tospecify which operating system is to be activated and optionally whichapplication(s) is/are to be executed in order to perform the functiondesired by the user.

[0061] The file defining a perimeter contains a unique identifier forthe perimeter and the definition of the hardware computer resources thatneed to be implemented in order to execute the operating activitycorresponding to the activity identifier recorded in the identity fileof said domain. For this purpose, a perimeter definition includes one ormore identifiers of cells in the platform 4, at least one reference tothe system disk containing the operating system to be executed, and inthis case one or more references to data disks containing theapplication(s) to be executed and/or the data to be processed. By way ofexample, the list 70 comprises in this case three domains referenced D₁,D₂, and D₃. The domain D₁ contains the definition of a perimeter P₁ andan identity file Id₁. The perimeter P₁ defined in this example comprisescells 30, 32, and 36 of the platform 4, together with data disks 10 andsystem disks 14. The identity file Id₁ contains an identifier of theactivity A₁, and identifiers of the application 20 and of the operatingsystem 24. The domain D₂ contains a file defining a perimeter P₂ and anidentity file Id₂. The perimeter P₂ defined in this example comprisesthe cell 34, the data disk 12, and the system disk 16. The identity fileId₂ contains an identifier of the activity A₂ and identifiers of theapplication 22 and of the operating system 26. The domain D₃ contains afile defining a perimeter P₃ and the identity file Id₁. The perimeter P₃comprises the cell 34, the data disks 10, and the system disk 14.

[0062] The perimeters P₁ and P₂ are represented diagrammatically bydotted lines in FIG. 1. The perimeter P₃ is represented by chain-dottedlines.

[0063] When a perimeter such as the perimeter P₁ comprising a pluralityof cells is activated on the platform 4, a single one of those cells isa master cell, while the other cells within the same perimeter are slavecells. Thus, this set of cells acts in fact as a single microprocessorunit. The master cell is determined automatically, for example, byselecting the cell within the perimeter having the lowest order number.In such a situation, only the IPMI hardware interface associated withthe master cell is used for sending to the management tool 9 eventsrecorded by the activity executed in the multiple-cell perimeter.

[0064] The common event log 72 is suitable for containing all of theevents recorded by each of the activities being executed or that havebeen executed on a perimeter configured on the platform 4. In this case,the events are received via the IPMI interface of the card 48 or 50. Inaddition, the common event log 72 is also suitable for containing all ofthe events generated by the hardware resources of the cells of theplatform 4, i.e. events detected directly by the cards 48 or 50 andtransmitted directly to the management tool without passing via the IPMIinterface. For this purpose, in the embodiment described herein, and asshown in FIG. 3, the log 72 is constituted by a table in a database. Thetable comprises four columns 80, 82, 84, and 86. Column 84 is forcontaining the recorded event and column 86 is for recording the instantat which said event occurred. Column 80 is for containing the identifierof the activity or the hardware resource that recorded the event whichappears in the same row. In the embodiment described herein, thehardware resource identifier is the identifier of the cell containingthe resource. Thus, in the description below, it is assumed that themost elementary element of the system 2 capable of recording an event inthe common log 72 is a cell. Column 82 is for containing a scopeattribute specifying the perimeters or activities which are authorizedto consult the event recorded in the same row. In this case, thisattribute can take three values:

[0065] “Source”, i.e. only the activity which recorded the event isentitled to consult the event;

[0066] “Local”, i.e. only the activity being executed on a perimetercontaining the cell that recorded the event is entitled to consult it;and

[0067] “All”, i.e. the event can be consulted by any activity regardlessof the perimeter on which it is being executed.

[0068] By way of example, the data occupying five lines 90 to 98 of thetable is shown. The content of these lines is described in greaterdetail below with reference to FIG. 4. Dashed lines in the table occupyrows that are not shown.

[0069] The computer 62 has management software 76. This softwareoperates under the control of an operator to define and activate newlogical domains in the system 2.

[0070] For this purpose, the software 76 includes a module 102 fordefining new domains and a module 104 for activating domains. The module102 is suitable under the control of an operator for defining newdomains and for recording them in the list 70. Thus, the module 102 isfor use by the operator to create new perimeter definition files and newidentity files. This module is also suitable for enabling the operatorto associate a perimeter definition file with an identity file in orderto form a new logical domain.

[0071] The module 104 is adapted to enable the operator to select fromthe list 70 a domain that is to be activated on the platform 4. Suchdomain activation consists firstly in configuring on the platform 4 theperimeter as defined in the selected domain, and secondly inautomatically launching on the configured perimeter the activity thatcorresponds to the identity file contained in the domain. In addition,the module 104 is suitable for enabling the operator to deactivate oneor more domains currently being executed on the platform 4.

[0072] The management software 76 is also suitable for automaticallysaving in the log 72 events sent by the interface cards 48 and 50. Forthis purpose, the software includes a module 106 for saving events inthe log 72, a module 108 for recording management parameters of apersonal event log, and a module 110 for reconstructing a personal eventlog.

[0073] The module 106 is suitable for saving in the log 72 all of theevents sent to the management tool 9 by the activities being executed orthe cells that are activated. For this purpose, the module 106 includesa submodule 112 for determining the scope of an event it has receivedand a submodule 114 for recording a new row in the log 72.

[0074] The submodule 112 is adapted to determine which scope attributevalue is to be recorded in column 82 of the log 72 for this event. Thissubmodule is therefore suitable for determining in respect of each eventthat is to be recorded which are the activities and/or the perimetersthat are to be authorized to consult the event. In the simplifiedembodiment described herein, the submodule 112 is associated with a listcontaining all kinds of event that might arise and need to beconsultable by all activities regardless of their perimeter.

[0075] The submodule 114 is suitable for determining the identifier ofthe activity or the cell that has sent the event. It is also suitablefor recording a new row in the log 72. The new line contains the eventthat has been sent, the identifier of the sender, the time and date ofthe event, and the scope attribute value as determined by the submodule112 in respect of the event.

[0076] The module 108 is suitable for recording the managementparameters of a personal event log specific to an activity in theidentity file associated with the activity. Thus, for example, themodule 108 is suitable in this case for recording the time and date ofthe most recent instruction to delete the personal event log of anactivity in the saved attribute provided for this purpose in theidentity file of that activity.

[0077] The module 110 serves to reconstruct or restore a personal eventlog specific to each activity on the basis of the data stored in the log72. For this purpose, it has a submodule 116 for selecting from the log72 those events that are consultable by a given activity. In this case,the events are those events which are associated with the identifier ofthe activity, those events which are associated with the identifier of acell contained in the perimeter on which the activity is being executed,and those events having a scope attribute with the value “All”.

[0078] The module 110 also has a submodule 118 for activating managementparameters of the personal event log reconstructed by the submodule 116.In particular, this submodule 118 is suitable for executing the mostrecent delete instruction saved in the identity file of thecorresponding activity.

[0079] The method of operation of the system 2 is described below withreference to FIG. 4 for the particular case of the domains initiallyactive on the platform 4 being the domains D₁ and D₂.

[0080] The method shown in FIG. 4 comprises, in chain-dotted lines, astage 130 of executing activity A₁ on perimeter P₁, a stage 132 ofexecuting activity A₂ on perimeter P₂, and a stage 134 of executingactivity A₁ on perimeter P₃.

[0081] The stages 130, 132, and 134 correspond respectively toactivating and executing the domains D₁, D₂, and D₃. The stages 130 and132 are separated from the stage 134 by a step 136 of deactivating thedomains D₁ and D₂ and then activating the domain D₃ on the platform 4.Hardware resources of the perimeter P₃ are common either with theperimeter P₁ or with the perimeter P₂, and as a result prior toconfiguring the perimeter P₃ on the platform 4, all of the necessaryhardware resources must be released, which in this case corresponds todeactivating perimeters P₁ and P₂.

[0082] The stages 132 and 134 are similar to the stage 130. As a resultonly stage 130 is described in detail herein for the particular case ofactivity A₁ and of perimeter P₁.

[0083] The stage 130 comprises a step 140 of the activity A₁ saving anevent, a step 142 of the cell 30 saving an event, and a step 144 of theactivity A₁ sending an instruction to modify its personal event log, anda step 146 of the activity A₁ consulting the personal event log.

[0084] Step 140 occurs when activity A₁ sends an instruction via theIPMI interface of the card 48, said instruction being to save a newevent. This step 140 is thus triggered by the software 76 of themanagement tool 9 receiving an event associated with an identifierindicating that this event was produced by activity A₁. During thisstep, the event received in this way is recorded in the log 72. Thisstep mainly comprises a substep 150 of determining the scope attributefollowed by a substep 152 of recording a new row in the log 72.

[0085] Substep 150 is implemented by the submodule 112 of the software76. This submodule 112 begins by comparing the event received with thelist of events that is associated therewith. If the event received isidentical with one of the events contained in the associated event list,then the scope attribute is given the value “All”. Otherwise, since theevent was sent by activity A₁ it is automatically associated with ascope attribute having the value “Source”.

[0086] Thereafter, during substep 152, the recording submodule 114records a new row in the table constituting the log 72, said rowcontaining the received event in column 84, the instant said eventappeared in column 86, the value of the scope attribute in column 82,and the activity identifier in column 80. In this case, by way ofillustration, activity A₁ records rows 90 and 98 in succession in thelog 72 during stage 130. Row 90 contains the identifier A₁, the value“Source”, event E_(a), and instant t_(a) respectively in columns 80, 82,84, and 86. Row 98 also contains the identifier A₁, the value “Source”,an event E_(e), and an instant t_(e), respectively in columns 80, 82,84, and 86.

[0087] Step 142 occurs when the software 76 receives an event that isgenerated directly by the cell without going via the IPMI interface orthe operating system. Such events relate, for example, to the operatingstate of one of the microcontrollers in the cell. During this step 142,a new event is recorded in the log 72. Step 142 includes a substep 154of determining the value of the scope attribute associated with thereceived event, followed by a substep 156 in which the event is recordedin the log 72. Substep 154 is performed by the submodule 112 fordetermining the value of the scope attribute. During this substep, thereceived event is compared with the list associated with the submodule112, and if this event is identical with one of the events contained inthe list, then the scope attribute is given the value “All”. Otherwise,the value of the scope attribute is set to “Local”.

[0088] The substep 156 is similar to the substep 152 except that it isthe identifier C₁ of the cell 30 that sent the event which is recordedin column 80 and not the identifier of the activity that sent the event.For example, the list associated with submodule 112 for determiningscope includes an event E_(d). In this case, the event E_(d) is assumedto have occurred at instant t_(d) in cell 30. Step 142 is then executedwhich leads to row 96 being recorded in the log 72. This row 96 containsthe identifier C₁, the value “All”, the event E_(d), and the instantt_(d) which are respectively recorded in columns 80, 82, 84, and 86.

[0089] When the activity A₁ sends an instruction to modify its personallog, step 144 is executed to record the modification instruction in theidentity file associated with the activity. During step 144, therecording module 108 receives the instruction to modify the personal logas transmitted via the IPMI interface of the card 48. This receivedinstruction is then stored in the saved attribute of the identity fileId₁ corresponding to the activity A₁ that sent the instruction. In thiscase, by way of illustration, the activity A₁ sends an instruction todelete the event log at instant t₁. Consequently, the recording module108 stores in the identity file Id₁ the fact that a delete instructionwas sent at instant t₁.

[0090] When the activity A₁ seeks to consult its personal event log, aconsultation instruction is sent via the IPMI interface of the card 48to the reconstruction module 110. The reconstruction module 110 thenexecutes the step 146. This step 146 includes a substep 160 ofreconstructing the personal event log specific to the activity A₁followed by a substep 162 of executing the modification instructionsapplied to said reconstructed personal event log.

[0091] During substep 160, the selection submodule 116 of the module 110selects from the log 72 those events which are consultable or accessibleby the activity A₁. The selection submodule 116 does this by executingthree selection operations 164, 166, and 168 either successively orsimultaneously. Selection operation 164 consists in selecting from thelog 72 only that set of events which is associated with the identifierof the activity consulting its personal event log, i.e. in this case theidentifier A₁. This operation thus leads to rows 90 and 98 only of thelog 72 being selected during stage 130. Selection operation 166 consistsin selecting only those events which are associated with an identifierof one of the cells in the perimeter P₁ on which the activity consultingits personal event log is being executed, i.e. in this case one of theidentifiers C₁, C₂, and C₄. This operation, in the present example, thusleads to row 96 of the log 72 being selected. Selection operation 168consists in selecting from the log 72 only those events which areassociated with an identifier different from the identifier of theactivity consulting the personal event log and different from theperimeter on which said platforms is being executed, but associated witha scope attribute that allows the event to be consulted either by theactivity A₁ or from the perimeter P₁. In this case, none of the rows inthe log 72 as described above satisfies these three criteria. Althoughthe scope attribute recorded in column 82 of line 96 is equal to “All”,this row is not selected in order to reconstruct the personal event logof activity A₁ since it has already been selected in operation 166. Atthe end of these three selection operations 164, 166, and 168, onlythose rows which have been selected are made consultable or accessibleby the activity A₁. These rows that are consultable or accessible by theactivity A₁ constitute a reconstruction of its personal event log.

[0092] During substep 162, the instruction execution module 118 acts onthe personal event log as reconstructed during substep 160 to apply theinstructions for modifying the personal event log that are recorded inthe identify file Id₁ of the activity A₁ which is consulting itspersonal event log. In this case, the submodule 118 applies to thepersonal event log reconstructed for the activity A₁ the deleteinstruction as recorded in the identify file Id₁. The instant t₁ isassumed in this case to be later than the instant t_(a) and earlier thanthe instant t_(d), so executing this delete instruction leads todeletion only of row 90 that has been selected for incorporation in thepersonal event log of the activity A₁. Thus, at the end of the selectionsubstep 160 and of the substep 162 for executing modificationinstructions, the personal event log specific to the activity A₁contains only rows 96 to 98. Only these events can be consulted by theactivity A₁ when it is executed on the perimeter P₁. In other words,step 146 consists in filtering the log 72 so as to select therefrom onlythose events which concern the activity A₁ when it is executed on theperimeter P₁. Thus, the view given to the activity A₁ of the log 72 isrestricted to events which relate to it and which comply with themanagement parameters that have been recorded in its own identity file.

[0093] Although steps 140, 142, 144, and 146 have been described in thatorder, they can naturally occur in any order. These steps are triggeredeither by the activity or by a cell within the perimeter.

[0094] During stage 132, the activity A₂ and the perimeter P₂ executesteps similar to the steps 140 to 146. These steps are therefore notdescribed in detail herein for this particular case, where the activityidentifier is now A₂ and the cell identifier is C₃. Thus, by way ofexample, it is assumed that during this stage 132, the activity A₂triggers the recording of row 94 in the common log 72. This row 94includes the identifier A₂, the value “Source”, an event E_(c), and aninstant t_(c) respectively recorded in columns 80, 82, 84, and 86. Inaddition, by way of example, the cell 34 triggers the recording of row92 that includes the identifier C₃, the value “Local”, an event E_(b),and an instant t_(b) respectively recorded in the columns 80, 82, 84,and 86.

[0095] Thus, at the end of stages 130 and 132, the common log containssimultaneously events that have been recorded by the activities A₁ andA₂, and also events that have been recorded from the perimeters P₁ andP₂.

[0096] During stage 134, the activity A₁ is being executed on theperimeter P₃. Again, during this stage 134, steps similar to steps 140to 146 are triggered either by the activity A₁ or by the cell 34. Thesesteps are therefore not described again.

[0097] However, in order to illustrate the operation of the system 2, anexample of a step of consulting the common log 72 is described againbelow.

[0098] The log 72 is assumed to be in the state shown in FIG. 3 and theidentifier Id₁ is assumed to include the delete instruction produced atinstant t₁. The instant t₁ is assumed to be later than the instant t_(a)and earlier than the instant t_(b). Under such conditions, the step ofreconstructing a personal log specific to the activity A₁ leads to rows90, 92, 96, and 98 being selected from the log 72. Rows 90 and 98contain the activity identifier A₁ in column 80, row 92 contains cellidentifier C₃ in column 80, and row 96 contains a scope attribute equalto “All”.

[0099] Thereafter, the substep of executing the modificationinstructions recorded in the identity file Id₁ lead to row 90 beingdeleted. Event E_(a) took place at an instant earlier than the mostrecent delete instruction contained in the identify file Id₁. Thus, thepersonal event log ends up comprising only rows 92, 96, and 98, and onlyevents that are consultable by the activity A₁ while it is beingexecuted on the perimeter P₃.

[0100] The system 2 thus enables an activity, while it is being executedon a current perimeter, to find all of the events that it has recorded,regardless of the perimeter on which it was being executed previously.In this way, when an activity is transferred from a first perimeter to asecond perimeter, events that were recorded while it was executing onthe first perimeter are not lost. For example, row 98 is consultable byactivity A₁ while it is executing on perimeter P₃.

[0101] The embodiment described herein presents the advantage that anevent recorded by a cell is accessible from all of the perimeterscontaining the cell. Thus, all of the information relating to aperimeter is incorporated in the personal event log of activitiesexecuted on the perimeter.

[0102] The management parameters of the personal event log specific toany particular activity are recorded by the system 2 in a memory whichis accessible from all of the perimeters, and the system executes themwhen a personal event log is being consulted. Thus, the personal eventlog returned to each activity complies with its own managementparameters, regardless of the perimeter on which it has been or is to beexecuted. For example, when transferring activity A₁ from perimeter P₁to perimeter P₃ row 90 which was deleted while it was executing onperimeter P₁ does not become available again while it is being executedon perimeter P₃.

[0103] If an event recorded by a given cell is of interest to all of theconfigured perimeters and/or all of the activities being executed orthat might be executed, then it is incorporated in all of the personalevent logs of the activities that are executed. For example, althoughevent E_(d) (row 96) was recorded by cell 30, this event can beconsulted by activity A₁ while it is being executed on perimeter P₃.Thus, by means of a scope attribute, for example, events of generalinterest can easily be made available to all of the configuredperimeters or to all of the executed activities.

[0104] The value of the scope attribute is not restricted to the threevalues described herein. By way of example, this attribute may be a listcomprising a plurality of activity identifiers and/or perimeteridentifiers that are authorized to consult the corresponding event.

[0105] The common event log 72 is described above as being in the formof a table in a database. In a variant, the common event log comprisesone file for each activity presently being executed or that has beenexecuted on the platform 4. Such a file contains an activity identifier,e.g. in its file name, together with all of the events that have beenrecorded by the activity. In addition, the common event log alsocomprises one file per presently configured perimeter or perimeter thathas been configured on the platform 4. This perimeter file includes aperimeter identifier, for example in its file name, and all of theevents recorded by cells in the perimeter. During the reconstructionsubstep, a personal event log is delivered to an activity by associatingthe recordings contained in the file having the identifier of saidactivity with those contained in the file having the identifier of theperimeter on which the activity was executed.

[0106] In a variant, the management tool 9 which is described above asbeing distinct from the platform 4 is integrated in the hardware of saidmultiple-cell computer platform.

[0107] In a variant, the identifier of the hardware resource that hasrecorded an event in the given common event log 72 is the identifier ofthe hardware component contained in a cell. This variant also has acorrespondence table suitable, for each identifier of a hardwarecomponent, for specifying which is the cell that contains said componentand thus which is the perimeter that contains it.

What is claimed is:
 1. A method of managing a personal event logspecific to an operating activity, the log containing events recorded bysaid operating activity while it is being executed on a perimeter ofcomputer hardware resources configured on a multiple-cell computerplatform, each operating activity containing at least one operatingsystem suitable for managing the computer resources of the perimeter onwhich it is to be executed, and the multiple-cell computer platformhaving a plurality of distinct computer hardware resource perimeterssuitable for being activated in succession or simultaneously on theplatform, the method comprising: while an activity is saving an event, astep of recording the event in a common event log together with anidentifier of the activity that is saving the event; and prior to anactivity consulting its personal event log, a step of reconstructing thepersonal event log from the common event log, said reconstruction stepincluding an operation of selecting from the common event log only thoseevents which are associated with the identifier of the activity in orderto include those events in the personal event log reconstructed for saidactivity.
 2. A method according to claim 1, wherein the computerhardware resources of perimeters are capable of generating events, andthe method further comprises a step of recording in the common event logan event that has been generated by a computer hardware resourcetogether with an identifier of the resource that has caused the event,and wherein the step of reconstructing a personal event log specific toan activity further includes an operation of selecting from the commonevent log only those events which are associated with the identifier ofa computer hardware resource contained in the perimeter on which saidactivity is being executed in order to include those events in thepersonal event log reconstructed for said activity.
 3. A methodaccording to claim 1, further comprising: while an activity is saving anevent, a step of recording in the common event log a scope attributeassociated with said event and specifying the activities which areauthorized to consult said event and/or the perimeters from whichactivities are authorized to consult said event, and wherein the step ofreconstructing a personal event log specific to an activity furtherincludes an operation of selecting from the common event log only thoseevents which are associated with a scope attribute authorizing saidevent to be consulted by the activity being executed and/or from theperimeter on which said activity is being executed in order to includethose events in the personal event log reconstructed for said activity.4. A method according to claim 1, further comprising: while an activityis sending an instruction to modify at least one event in its personalevent log, a step of recording in a file said instruction in associationwith an identifier of the activity, which file is accessible by theactivity from all of the perimeters of the platform; and prior to anactivity consulting its personal event log, a step of executing themodification instruction applied to the personal event log asreconstructed for said activity during the reconstruction step.
 5. Asystem for managing a personal event log specific to an operatingactivity while it is being executed, the system comprising: amultiple-cell computer platform; a management tool suitable for definingcomputer hardware resource perimeters and for activating said perimeterson the platform simultaneously or in succession, each perimetercomprising one or more calculation cells; and means for storingoperating activities, each operating activity comprising at least oneoperating system suitable for managing the computer resources of theperimeter on which the activity is to be executed; the system furthercomprising: a memory containing a common event log suitable for storingthe events recorded by all of the operating activities; a module forrecording events in the common event log, said events being generated byeach operating activity and being associated with an identifier of theactivity causing the event to be saved; and a reconstruction module forreconstructing a personal event log specific to an operating activityfrom a common event log, the reconstruction module including a selectionsubmodule for selecting from the common event log only those eventswhich are associated with the identifier of said operating activity inorder to include those activities in the personal event logreconstructed for said activity.
 6. A system according to claim 5,wherein the personal event log specific to an operating activitycontains events recorded by the computer hardware resources of theperimeter on which the activity is being executed, and the systemfurther comprises a module for recording in the common event log anevent generated by a computer hardware resource of the perimeter inassociation with an identifier of said resource, and wherein the modulefor reconstructing a personal event log specific to an activity furthercomprises a submodule for selecting from the common event log only thoseevents which are associated with an identifier of a computer hardwareresource contained in the perimeter on which said activity is beingexecuted, in order to include those events in the personal event logreconstructed for said activity.
 7. A system according to claim 5,further comprising a module for saving in the common event log a scopeattribute associated with each event and specifying the activities whichare authorized to consult said event and/or the perimeters from whichthe activities are authorized to consult said event, and wherein themodule for reconstructing a personal event log specific to an activityfurther comprises a submodule for selecting from the common event logonly those events which are associated with a scope attribute thatauthorizes said event to be consulted by the activity being executedand/or from the perimeter on which the activity is being executed inorder to include those events in the personal event log reconstructedfor said activity.
 8. A system according to claim 5, further comprising:a recording module for recording instructions to modify at least oneevent in the personal event log specific to an activity, said recordingmodule being suitable for recording in the memory said modificationinstructions in association with an identifier of the activity that hasgenerated the instruction; and a module for executing modificationinstructions recorded by an activity in the memory, said modificationinstructions being applied to the personal event log reconstructed forsaid activity by the reconstruction module.
 9. A memory for storinginformation for use in a system for managing a personal event logaccording to claim 5, the memory containing a common event logcontaining a list of events saved by a plurality of different operatingactivities, each of said events being associated with an identifier forthe activity which saved it.
 10. An information storage memory accordingto claim 9, wherein the common event log also contains a list of eventssaved by computer hardware resources contained in perimeters, each ofsaid events being associated with an identifier of the computer hardwareresource that saved it.
 11. An information storage memory according toclaim 9, wherein the common event log contains a scope attributeassociated with each saved event, said scope attribute indicating whichactivities are authorized to consult said event and/or the perimetersfrom which activities are authorized to consult the event.